Fig. 3. Elevated dietary salt intake increases the expression of NKCC1 in branchial mitochondria-rich cells. Localisation of Na⁺/K⁺-ATPase (NKA; red), NKCC1 (green) and nuclei (blue) in gill sections from (A) control or (B,C) salt-fed fish. Areas of co-localisation of NKA with NKCC1 appear as yellow/orange. D is a representative image depicting a gill section from which both primary antibodies were omitted. Arrows in A indicate cells exhibiting NKA immunofluorescence, and in B co-localisation of NKA and NKCC1. Scale bars, 10 µm.